1. Field of the Disclosure
The present disclosure relates to a driving printed circuit board for a display device and a display device having the driving printed circuit board for a display device, and more particularly to a driving printed circuit board (PCB) for connecting an electronic device for a display device to a display panel, and a display device having the driving PCB.
2. Description of the Prior Art
With the development of the information society, various types of requirements for a display device for displaying an image are increasing and, recently, various display devices, such as a liquid crystal display (LCD), a plasma display panel (PDP), and an organic light emitting diode display device (OLED), are being used.
An LCD includes an array substrate including a thin film transistor, an upper substrate including a color filter, a black matrix and/or the like, and a liquid crystal material layer formed between the array substrate and the upper substrate. The LCD is a device in which an arrangement state of a liquid crystal layer is controlled according to an electric field applied to both electrodes of a pixel area. Therefore, transmittance of light is controlled, and thus an image is displayed.
A display panel of the LCD is defined as an active area (AA), which provides an image to a user, and a non-active area (NA), which is adjacent to the AA. The display panel is commonly manufactured by combining a first substrate with a second substrate. The first substrate is the array substrate, in which the pixel area is defined by the forming of the thin film transistor. The second substrate is the upper substrate, in which the black matrix and/or the color filter layer are formed.
The array substrate or the first substrate in which the thin film transistor is formed includes a plurality of gate lines (GLs) extending in a first direction, and a plurality of data lines (DLs). One pixel area (e.g., P) is defined by each gate line and each data line. In one pixel area (e.g., P), at least one thin film transistor may be formed, and a gate electrode or a source electrode of each thin film transistor may be connected to each gate line and data line.
In addition, in order to provide a gate signal and a data signal necessary to drive each pixel to each gate line and data line, a gate driving unit (i.e., a gate driving circuit), a data driving circuit or the like is formed in the NA or outside of the panel.
Among these, the gate driving circuit may be formed on the NA of the display panel in a process of forming various signal lines and a pixel of the display panel. Thus, the gate driving circuit may be implemented as a gate in panel (GIP) type in which the gate driving circuit is included in the panel. However, the gate driving circuit and the data driving circuit may be included in the same driver IC and may be separately disposed under the display panel.
Meanwhile, the display panel including the data driving circuit (i.e., D-IC) may be expressed as a liquid crystal monitor. The liquid crystal monitor is connected to a customer system such as a mobile phone, a PC, or a tablet PC, receives a data signal from the customer system, and is operated as a display device for the customer system.
In addition, a driving printed circuit board, which is connected to the liquid crystal monitor to provide various signals to the gate driving circuit and the data driving circuit included in the liquid crystal monitor, is provided. Various driving elements including a timing controller are mounted on the driving printed circuit board. One end of the driving printed circuit board (PCB) is coupled to the liquid crystal monitor through a flexible printed circuit board (FPC) or a flexible circuit film, and another end of the driving PCB is connected to a connection unit of the customer system through a connector (i.e., CNT) unit in which various terminals or pads are formed.
Meanwhile, in order to provide an electrical stability of various signal lines formed in a main circuit unit of the driving PCB, at least one dummy ground pad may be formed in the connector (i.e., CNT) unit of the driving PCB for the customer system. Some of the ground pads may not be electrically connected to a ground, and may be floated.
As described above, the ground pad floated in the connector (i.e., CNT) unit of the driving PCB for the customer system may possess a static electricity or an external inflow charge, and then the static electricity or the external inflow charge may flow into the liquid crystal monitor while connecting the driving PCB with the customer system. Thus, the ground pad may bring about various defects to the liquid crystal monitor.